Phase Self-excited Induction Generator Research Articles

Step by step approach for developing analytical and experimental research facilities of a three-phase self-excited induction generator

Self-excited induction generators (SEIGs) have been rigorously investigated in last few decades owing to their suitability for standalone renewable energy applications. Various issues pertaining to their modeling and control are quite aptly addressed in several analytical and experimental studies. However, these analyses are often focused on elaboration of proposed innovations and findings while the important details on modeling and implementation of SEIGs are left to be explored by readers. In this paper, a step by step approach for the mathematical modeling of three-phase self-voltage regulating, short shunt SEIG in stationary reference frame is explained. Subsequently, the developed d-q model of SEIG is implemented in terms of a simulation model. The developed model is then employed to carry out performance analysis of 3-phase, 2.2 kW SEIG supplying R-L load. All the results are verified with good accuracy in a SEIG test-rig whose details are included in the paper. The prime objective of this work is to provide a consolidated source for developing research resources of a self-voltage regulating three phase SEIG.

Design and Simulation of Current Sensor based Electronic Load Controller for Small Scale Three Phase Self Excited Induction Generator System

In standalone renewable energy systems, the power balance methods must exist to match the generated power and load demand; otherwise the excess power creates the disturbance in terms of voltage and frequency fluctuations. This paper presents a design and simulation of an electronic load controller (ELC) for the power balance in constant power prime mover-coupled three phase self-excited induction generator (SEIG) system. A current sensor based ELC is designed in such a way that to operate the generator unit always at its full capacity by coordinating between the two load systems termed as main and dump load. The controller unit has an uncontrolled 3-phase full-bridge rectifier circuit, a logically controlled insulted-gate bipolar transistor (IGBT) chopper switch, and a current sensor. The current sensor provides the feedback signal to the gate trigger circuit of IGBT and which inevitably controls the ON/OFF position of the switch. The ON condition of switch means a partial or full portion of generation power is diverted to the dump load, and the sum of both loads is equal to the rated capacity of SEIG. The proposed system is simulated in MATLAB, and the power balance is achieved with help of ELC. The voltage regulation of SEIG is addressed by adding extra reactive power (VAR) compensation. Further, in this study, the basic configuration of SEIG and the importance of self-excitation phenomena for voltage generation are also highlighted.

A Comprehensive Overview of Single–Phase Self-Excited Induction Generators

The use of induction generators for electricity production in small power isolated systems represents the topic for a wide research area. As in such topologies single-phase consumers are predominant, besides three-phase induction generators with adequate balancing circuits, single-phase induction generators qualify as a reliable alternative. In the last 38 years, a significant number of research papers have tackled the problems related to the autonomous operation of single-phase induction generators (SPIGs) such as determining excitation capacitors values and their optimal arrangement, ensuring stable operation in terms of voltage and frequency balancing under varying loads and finally enhancing the quality of the energy delivered to the isolated single-phase consumers. While in case of simple topologies the operation of SPIGs is mainly investigated for fundamental electric parameters dependence with loading, excitation capacitance and speed, the use of power electronics based converters ensures stable operation over a wide range of varying/non-linear loads. This paper presents a comprehensive overview of the literature dedicated to SPIGs, focusing on several significant aspects such as main topologies, modeling, steady-state analysis and performance investigations.

Series Compensation of Self Excited Induction Generator Feeding Domestic Load

This paper presents a series compensated three phase self-excited induction generator feeding domestic load. This paper focus on the dynamic behaviour of Uncompensated SEIG and series compensated SEIG feeding dynamic load such as three phase induction motor. Various dynamic characteristic of SEIG feeding three phase induction motor is obtained by matlab/simulation and laboratory experimentation. The uncompensated and series compensated results is then compared to improve the voltage regulation of SEIG.

Utilization of Self-Excited Three-Phase Induction Generator System

In this paper the analysis of a three phase self-excited induction generator system under transient and steady states with various load conditions are presented. In rare area where assumed no national grid is present, but hydro or wind energy may be available a cheap prime mover, such as micro hydro or wind turbine may be applied, which has fluctuating speed. In order to obtain self-excitation, a voltage source inverter based on sinusoidal pulse width modulation strategy has been proposed. The generated voltage and frequency are regulated by adjusting modulation index value. The value of modulation index depends also on the DC voltage level obtained from batteries or solar panels. The proposed system has been also examined without main dc power source , but with the existence of bank capacitor located at the dc link side of the inverter, in this case the generated active power should be equal to/or greater than the required active load power. DC chopper load has thus been utilized to absorb the extra active power, this will control the DC voltage across the capacitor while modulation index will control the system AC output voltage. The generated voltage waveform contains harmonic orders around and higher than the switching frequency, therefore three-phase high passive filter has been used to eliminate the harmonics effects. As a result the machine terminal voltage and frequency values are regulated and maintained constant for different types of loads at different prime mover speed cases. In all these cases, total harmonic distortion values are within the standard values.

Performance analysis of self-excited induction generator for different excitation and loading condition in wind turbine application

To ensure the complete control of AC machine, state analysis is highly required during the dynamic modelling. In this paper, a mathematical model of the self-excited induction generator (SEIG) is developed to analyse its operation in wind energy systems. A generalised steady state model using d-q stationary reference frame of such a three phase SEIG has been developed. The model has been analysed for balanced and unbalanced excitation condition. Moreover, the effect of wind speed and pitch angle in generator response is observed. Eventually, the model is tested for static and dynamic loads. The analysis of the results could help to determine the efficiency solutions for the system to supply isolated areas even when the loads are unbalanced. The derived equations and developed model are verified through the simulation results of MATLAB simulator.

Performance analysis of self-excited induction generator for different excitation and loading condition in wind turbine application

To ensure the complete control of AC machine, state analysis is highly required during the dynamic modelling. In this paper, a mathematical model of the self-excited induction generator (SEIG) is developed to analyse its operation in wind energy systems. A generalised steady state model using d-q stationary reference frame of such a three phase SEIG has been developed. The model has been analysed for balanced and unbalanced excitation condition. Moreover, the effect of wind speed and pitch angle in generator response is observed. Eventually, the model is tested for static and dynamic loads. The analysis of the results could help to determine the efficiency solutions for the system to supply isolated areas even when the loads are unbalanced. The derived equations and developed model are verified through the simulation results of MATLAB simulator.

Control Topologies for 3-Phase SEIG used in Small Hydro Power Plant Feeding Isolated Domestic Load in Remote Mountainous Region

Objectives: This paper is to highlight the various control topologies used in 3-phase Self-Excited Induction Generator (SEIG) used in pico-hydro power generation system feeding isolated load. Methods/Statistical Analysis: The various topologies of these controllers which are also known as Electronic Load Controllers (ELC) include conventional as well as STATCOM based controllers using various power electronics devices for power system parameters regulations and power quality control. The Self-excited induction generators are most suitable for pico and micro hydro power generation systems feeding isolated load due to their advantages over conventional synchronous generators. Findings: In isolated mode of operation of self-excited induction generators, a suitable control is necessary to maintain the voltage & frequency of the generated output within permissible limits under varying loading conditions. This is achieved by using an Electronic Load Controller (ELC) and dump load in the system. The main aim of the control strategy is to control the voltage output of SEIG and to maintain the desired frequency of the generated output. These electronic load controllers regulate the dump load in the system so that total load seen by SEIG remains constant under varying consumer load conditions and thus maintaining the frequency of the system. From the analysis of various types of these controllers, it is found that simplest of the electronic load controller is conventional diode rectifier based ELC. However, it suffers with the problems of harmonics in the circuit. Modern ELCs use voltage source converters along with different transformer configurations for better power quality control and better voltage and frequency regulations under different operating conditions. Improvements: Fast computational capabilities of DSP are also used to control the STATCOM switches and chopper circuit in ELC for better and fast control. The use of different transformer configurations such as star-delta and zigzag type provide neutral path for 3-phase, 4-wire system apart from eliminating the 3rd harmonics in the system.

Modeling, implementation and analysis of a high (six) phase self excited induction generator

Dual d-q model of six phase-self excited induction generator (6Ph-SEIG) developed in stationary reference frame is proposed in this paper. Developed model, implemented in terms of a simulation model, is utilized to evaluate no-load and on-load characteristics along with the estimation of dynamic parameters of studied 6Ph-SEIG for each working condition. Simulation results are verified on the implemented 6Ph-SEIG test-rig with high accuracy. Inherent loading limit of 6Ph-SEIG is obtained as 68% of the rated capacity with the evaluated optimum excitation capacitance of 4μF per phase. The reactive power of SEIG varies from 4400 var to 600 var from no-load to maximum load of 1377W with a corresponding change in magnetizing current from 4A to 0.64A.

Voltage regulation approach to a self-excited induction generator: Theoretical study and experimental validation

Summary This article describes an accurate steady-state analysis of a stand-alone 3-phase self-excited induction generator (SEIG). This analysis, based on the Newton-Raphson algorithm, has shown that the system performance is greatly affected by the parameters related to the availability of primary energy, load variations, and excitation capacitor values. These parameters explain the stator voltage fluctuations and the output frequency decrease. To avoid any interruption of the excitation process and to ensure a good quality of the stand-alone minigrid, a three-phase voltage regulator (TPVR), based on switched capacitors, is proposed to keep the terminal SEIG voltage constant. The control algorithm and the regulation process are implemented using a microcontroller. The SEIG-TPVR is experimentally developed, and a variable capacitor bank is constructed. The experimental investigations on a 1.5-kW induction machine confirm the efficiency of the whole suggested system.

Design and Implementation of a Multi-Phase Induction Machine Operating in generating Mode for Power Generation

Self-excited induction generators are increasingly being used in remote areas to generate electrical power from both conventional and nonconventional energy sources. This paper investigates a multi-phase self excited induction generator designed for its six-phase operation. Evaluations were made out on the basis of the machine performance which includes voltage and current characteristics at different conditions. The model used for analyzing the machine behavior has two three phase winding sets. In this paper the analytical modeling of a self excited induction generator operating in six phase mode has been made and the analysis of the machine has been carried out with symmetrical phase displacement between the six stator windings. The dynamics of the self excitation process of the six phase self-excited induction generator has been made which was simulated and analyzed.

Steady State Modeling and ANFIS Based Analysis of Self-Excited Induction Generator

Self-excited induction generator (SEIG) has the ability to generate power at varying speed, which facilitates its application for wind energy conversion in remote and windy areas. Estimation of the generator behavior under actual operating conditions is essential, but the SEIG analysis with conventional techniques take long time with fatigued mathematical procedures. This paper presents a new technique for the performance analysis of a three phase SEIG supplying an isolated resistive load using adaptive neuro-fuzzy inference system (ANFIS). Proposed ANFIS model has been implemented to predict the effect of prime mover speed, capacitance and load on generated voltage of SEIG. Experimental data is used for the training of ANFIS. Results obtained from the trained have been compared with the experimental results. The comparison confirms the validity and accuracy of the ANFIS based modeling of induction generator.

The Process of Self Excitation in Dual Three-Phase Induction Generator

In this paper the phenomenon of self excitation in dual three-phase induction generator (DTPIG) is examined and a physical interpretation of how self excitation occurs is presented. The proposed steady-state model of a dual three phase self-excited induction generator for stand-alone renewable generation dispenses with the segregating real and imaginary components of the complex impedance of the induction generator. Steady state performances and characteristics of different configurations are clearly examined and compared. The analytical results are found to be in good agreement with experimental results.

An analytical performance comparison of two winding and three winding single phase SEIGs

This paper presents an in-depth comparison of two possible schemes to supply 1-phase loads from self excited induction generators (SEIGs). These schemes employ 2-phase (asymmetrical) and 3-phase (symmetrical) stator windings with a squirrel cage (brushless) rotor and appropriate capacitor topologies. Among the different topologies proposed in literature for good voltage regulation and maximum power output, this paper investigates both the schemes to arrive at best configuration and provides a critical comparison to guide prospective users. General analytical models for both systems are presented and simulation methods explained. Comparison is made between both machines built in same frame based on computed and measured results. For constant speed prime movers such as bio-energy fed engines and hydro-turbines, it is possible to evolve a simple and user-friendly system based on this study that shows great promise for remote area electrification.

Switching control of self-excited induction generator under steady state conditions

paper presents a Matlab based simulation model to regulate the terminal voltage and frequency of three phase self-excited induction generator using switching control . A new block in Matlab has been developed for steady state analysis of three phase self-excited induction generator wherein the output voltage and frequency of generator remains constant irrespective of changes in consumer load. The model involves a switching system comprising of number of suitable resistive elements connected in parallel to the load. Simulated results on a test machine are found to be well within the tolerable limits.

DSP-based fuzzy load controller for single phase self-excited induction generator

This paper presents the design and implementation of a fuzzy logic-based load controller to regulate the voltage and frequency of single phase self-excited induction generator (SEIG), suitable for standalone operation. The SEIG can be used to generate constant voltage and frequency if the load is maintained constant at its terminals. Moreover, under such operation, SEIG requires constant capacitance for excitation resulting in a fixed-point operation. For this purpose, a suitable control scheme is to be developed such that the load on the SEIG remains constant despite the change in the consumer load. A DSP-based fuzzy load controller has been developed based on equal time ratio control (ETRC) AC chopper controllable load which gives non-linear control with fast response and injects minimum harmonics in the system. The transient behaviour of DSP-based SEIG-fuzzy load controller system at different operating conditions such as application and removal of static (resistive and reactive) load is investigated.

Voltage Controller of a Single Phase Self-Excited Induction Generator

This paper presents the design of a low cost voltage controller of a single phase Self-Excited Induction Genera- tor (SEIG). The control scheme is based on the measurement of users load voltage and controlling the dump load power using an Analogue Input Power Controller (AIPC). The controller output varies from 2 -10V and it controls the output AC power going to a resistive dump load. A PI type controller is designed to adjust the dump load as the users load varies to maintain a constant voltage across the load. The system voltage regulation is tested by sudden change in the users load. This paper presents the system description, controller design, and test results.

Steady state modeling and fuzzy logic based analysis of wind driven single phase induction generators

This paper describes a new generalized and efficient model using graph theory and fuzzy logic based steady state analysis of wind driven single phase single winding self-excited induction generator (SEIG) with or without series compensation. Steady state generalized model of single phase SEIG is formulated using nodal admittance method based on graph theory. This dispenses with tedious work of segregating real and imaginary components of the complex impedance of induction generator for deriving the specific models for each operating mode. Graph theory based matrix equations are easier to modify in order to account for specific effects such as short/long-shunt, core-loss, etc. The resulting equations have excellent symmetry which makes the analysis very easy, fast and accurate. The matrix equations developed by nodal admittance method are solved by fuzzy logic technique to predetermine the steady state performance of single phase SEIG. The experimental and theoretical results are found to be in close agreement.

Capacitive VAr requirements for wind driven self-excited induction generators

Abstract This paper presents the capacitive VAr requirements of a three phase pole changing self-excited induction generator and a single phase self-excited induction generator, used as isolated power sources by a constant speed or a variable speed prime mover, to obtain the desired voltage regulation at various values of load and speed. Different performance criteria such as constant terminal voltage or constant air gap flux have been considered. The developed mathematical model using nodal analysis based on graph theory is quite general in nature and can be used for any combination of the unknown variables such as magnetizing reactance (XM) and frequency (F) or capacitive reactance (XC) and frequency (F) or capacitive reactance (XC) and speed (υ). The proposed model completely avoids the tedious and erroneous manual work of segregating the real and imaginary components of the complex impedance of the machine for deriving the specific model for each operating modes. Moreover, any element, like the core loss component, can be included or excluded from the model if required. Next, to obtain the capacitive VAr requirements of a three phase pole changing self-excited induction generator and a single phase self-excited induction generator, a fuzzy logic approach is used for the first time to find the unknown variables using the above model. The results are presented in a normalized form so that they are valid for a wide range of machines and would be useful for the design of voltage regulators for such generators.

Generalized State-Space Modeling of Three Phase Self-Excited Induction Generator For Dynamic Characteristics and Analysis

This paper presents the generalized dynamic modeling of self-excited induction generator (SEIG) using state-space approach. The proposed dynamic model consists of induction generator; self-excitation capacitance and load model are expressed in stationary d-q reference frame with the actual saturation curve of the machine. An artificial neural network model is implemented to estimate the machine magnetizing inductance based on the knowledge of magnetizing current. The dynamic performance of SEIG is investigated under no load, with the load, perturbation of load, short circuit at stator terminals, and variation of prime mover speed, variation of capacitance value by considering the effect of main and cross-flux saturation. During voltage buildup the variation in magnetizing inductance is taken into consideration. The performance of SEIG system under various conditions as mentioned above is simulated using MATLAB/SIMULINK and the simulation results demonstrates the feasibility of the proposed system.